This invention relates to the identification and tracking of batches of objects through a manufacturing process. More specifically, it relates to a method and apparatus for monitoring the progress of a plurality of batches of semiconductor wafers or memory disks through processing operations and for providing status coding at desired processing stations.
In the semiconductor manufacturing industry semiconductor wafers are moved through a manufacturing plant to a number of different locations where the semiconductor wafers are etched, cleaned, processed using photolithography operations, tested and subjected to various other manufacturing testing and processing operations. Similarly, memory disks are also moved through a sequence of manufacturing operations in a manufacturing facility.
It is common in the industry to handle the wafer or memory disks in batches contained within carriers specifically designed for the purpose of supporting the wafer or memory disks in the proper position for the manufacturing and processing machinery which may either process the disks or wafer while they remain in the carriers or remove them for a processing operation and then returns them to the carriers. A batch is defined and used hereinafter to mean one or more (up to the capacity of the carrier) of the semiconductor wafer or memory disks.
In a manufacturing plant, it is desirable to track the progress of a batch of wafer or memory disks through the manufacturing process. Moreover, it is desirable to be able to maintain at the batch, as opposed to a remote location, certain information relating to the processing or progress of the batch.
Use of transponder tags in the processing of disks has been disclosed in U.S. Pat. No. 4,827,110 issued to Rossi and Saucer and assigned to the assignee of this invention. Rossi et al. disclosed a method and apparatus in which a transponder tag was secured to the outside surface of a vertical wall.